I'm trying to implement my app architecture loading in the app struct an object containing the data to be shared in all the views of the app through an environment object:

@main
struct SMT_testingApp: App {
    
    @StateObject private var dataManager = DataManager()
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(dataManager)
        }
    }
}

Here's the Datamanager class publishing the var containing the data:

class DataManager: ObservableObject {
    
    @Published var SMTItemList: [SMTItem] = [SMTItem(id: UUID(), itemDesc: "", itemCreaDate: Date(), itemUpdDate: Date(), itemTags: [], linkedItemsUID: [])]
    
    var urlFile: URL {
        getDocumentsDirectory().appendingPathComponent("/SMT.json")
    }
    
    init() { loadData() }
    
    func getDocumentsDirectory() -> URL {
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        return paths[0]
    }
    
    func loadData() {
//...

After here the View that contain the instance of his view model:

struct ContentView: View {
    @StateObject private var viewModel = ViewModel()
    
    var body: some View {
        List(viewModel.dataManager.SMTItemList) { item in
            SMTItemView(item: item)
               }
    }
}

struct SMTItemView: View {
    var item : SMTItem
    var body: some View {
        Text("Item desc: \(item.itemDesc)")
    }
    
}

And finally, the view model that contains the environment object with the data.

extension ContentView {
    class ViewModel: ObservableObject{
        @EnvironmentObject var dataManager: DataManager
    }
}

Now, the code is built correctly but at runtime I obtain this error in the content View:

What I'm doing wrong? Is correct implementing an architecture that way (one enviroment object with the data and many views/view models) ? Thanks

CodePudding user response：

@EnvironmentObject must be in view scope, not view model class. Like

struct ContentView: View {
    @StateObject private var viewModel = ViewModel()
    @EnvironmentObject var dataManager: DataManager    // << here !!

    var body: some View {
        List(dataManager.SMTItemList) { item in
            SMTItemView(item: item)
               }
    }
}